BL10是生產二十二碳六烯酸 (C22:6 n-3, DHA) 的優良微藻。進行試量產時，其可在72小時內達到乾重110 g L-1與近20 % 的DHA含量，然而此時亦有高達30 % 的十六碳飽和酸 (C16:0, PA)及7 % 的二十二碳五烯酸 (C22:5 n-6, DPA)。由於前者會造成藻油在低溫條件下凝固，影響產品賣相，後者則會和DHA在人體內產生拮抗作用，降低產品的功效。為解決上述問題，此研究利用培養基鹽類的濃度及種類、葡萄糖的濃度、供氧量的調整，以及脂肪酸生合成抑制劑的添加等方法嘗試改善。
研究結果顯示，隨著鹽度的降低，DHA產量有逐漸升高的趨勢，並在鹽度為5 ppt，酵母萃出物、葡萄糖分別為9及90 g L-1的條件進行批次培養，可以獲得最理想的DHA產量 (9.8 g L-1)、以及油質 (PA/DHA = 0.63、DPA/DHA = 0.17)。當培養基的鹽度低於5 ppt 及過多的硫酸根離子存在的情況底下，會使得PA的比例會大幅提昇。而在葡萄糖濃度及碳氮比越高的情況下，PA及DPA的比例越高。此外在細胞停止分裂，開始大量累積油脂之際，降低溶氧或添加cerulenin (fatty acid synthase抑制劑) 的作法，可以明顯降低DPA或PA的比例，然又不致於影響DHA的產量。
因此欲改善BL10油脂比例應避免在鹽度小於5 ppt、硫酸根離子過多、碳氮比或葡萄糖濃度過高的條件下培養，並於細胞分裂停止時降低供氣量，此外未來更可利用生物技術的方法抑制fatty acid synthase以改善油脂。

Microalga BL10 is a good candidate for commercial DHA (docosahexaenoic acid, C22:6 n-3) production. During 72 hours industrial fermentation, the biomass can reach 110 g L-1 and contain almost 20% DHA. However, it also exists 30 % PA (palmitic acid, C16:0) and 7 % DPA (docosapentaenoic acid C22:5 n-6). The former (PA) would cause the algae oil to be congealed under low temperature condition, which affects the product appearance; the latter (DPA) would against DHA function in human body. To solve above mentioned problems, in this study we try to modulate the fatty acid profile by changing the culture environment, such as salinity, salt types, glucose concentration, dissolved oxygen level and fatty acid synthesis inhibitor addition.
Result showed that as the salinity decreased, the DHA yield had elevated gradually. The best DHA yield (9.8 g L-1) and the oil quality (PA/DHA = 0.63、DPA/DHA = 0.17) occurred when the salinity was controlled at 5 ppt, yeast extract at 9 and glucose at 90 gL-1 . PA content enhanced when the culture medium salinity was lower than 5ppt plus excess of sodium sulfate addition. It was also showed that the high glucose density and high C/N ratio resulted in the higher PA and DPA content. However, in the case of cell division stopped, decreasing dissolve oxygen level or treating with cerulenin (a fatty acid synthase inhibitor) would obviously reduce the DPA and PA level without affecting of DHA yield.
In order to improve BL10 oil quality, we should avoid culturing under the conditions of salinity less than 5 ppt, excess of sulfate ion concentration, glucose density or C/N ratio. It’s also more practical to lower the DPA content by reducing dissolve oxygen level as the cell division stopped stage. Furthermore, it could be possible to improve oil quality in the future through biotechnological method by inhibiting fatty acid synthase activity.

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